RGEN Shorts Rebuild Ahead of July 28 Earnings

Repligen Corporation heads into its July 28 quarterly print with short interest quietly rebuilding, options traders hedging more heavily than usual, and analysts broadly constructive but split on how fast recovery comes.

The most notable shift this week is in the short book. Short interest has climbed to nearly 11% of the free float — close to the 52-week high — after rising about 1.9% over the past week and adding steadily since early July. That follows a brief dip in late June and early July, which now reads as a short-covering episode that has fully unwound. The rebuild is measured rather than panicked: roughly 146,000 additional shares added to the short position over the past two weeks, pushing the total above 6.16 million shares. Days to cover sits near 4.6, meaning any sharp upside move on earnings would squeeze a meaningful portion of that position quickly.

The borrow market, however, offers shorts no reason to panic yet. Availability is ample at roughly 353% — meaning there are more than three shares available to borrow for every one currently lent out — which is well within the normal range and actually somewhat looser than the 52-week low near 313%. Cost to borrow has drifted lower on the week to about 0.52%, down from a mild spike near 0.63% earlier in July. That combination — high short interest but easy borrow conditions — suggests the bears are positioned but not squeezed. Options, though, tell a slightly more defensive story. The put/call ratio has risen to 1.83, above its 20-day average of 1.75, with a z-score of around 1.4. That's not extreme, but it marks the most defensive options posture in about a month, consistent with hedging into a binary event.

The Street remains broadly positive, though with enough internal disagreement to make the consensus feel fragile. Benchmark upgraded to Buy earlier in July with a $185 target. Evercore ISI raised its target to $160 while staying at Outperform the same week. Those two moves set an optimistic tone, but they sit against a backdrop of earlier trims: JPMorgan cut its target to $165 after the last print, HSBC lowered to $150, and Wolfe Research came in fresh at $145. The mean target is $178, implying roughly 30% upside from the current price near $137 — but the range of targets is wide, from $145 to $185, which reflects genuine uncertainty about the pace of bioprocessing demand recovery. The bull case centres on accelerating revenue from CDMOs and biopharma customers, with Process Analytics revenue up more than 50% year-over-year at the last update. Bears point to margin pressure, with the adjusted operating margin guided near 13.5% and questions around large-customer order concentration. EV/EBITDA has compressed about 3.3 turns over the past month to roughly 40x — still elevated, but the direction of travel is downward.

T. Rowe Price added nearly a million shares in Q2 to become the largest institutional holder at 11.1% of shares outstanding, a meaningful commitment from one of the stock's most visible long-term holders. BlackRock also added modestly. On the insider side, the CFO sold small tranches at $145 and $150 in June and July respectively — routine in scale but directionally worth noting given the stock is now trading below both sale prices.

The last earnings print in May saw the stock fall nearly 4% on the day before recovering about 6% over the following week, which has been a recurring pattern: immediate disappointment followed by a digest-and-recover. With shorts at near 52-week highs and options skewed toward puts, the setup into July 28 is one where any upside surprise on guidance or order visibility could produce a sharp unwind of the short position, while a miss on margins would likely validate the bears who have been rebuilding patiently all month.